Many people have both a mobile station (also called wireless telephone, cell phone) and a wireline telephone. Each of these telephones have its own respective directory number (DN). In order to call the user of these telephones, a caller must know both of the telephone numbers. Further, the caller sometimes makes multiple calls before the person is found. While service providers have several features that attempt to alleviate this multiple DN problem, none of them provide efficient "one person, one number" service.
One such feature is call forwarding. A user with multiple telephones dials a code number at one telephone, and then enters the directory number of the telephone to which calls are to be forwarded. The user, however, has to remember to enter and cancel call forwarding whenever he/she changes telephones. Some service providers use special telephone numbers (such as telephone numbers with "700" as the area code) wherein all calls to that number are routed to the last telephone registered. However, the subscriber still has to remember to register to keep all calls forwarded to the proper telephone.
Some service providers attempt to terminate a call to a DN to several different telephones, either serially (dialing a list of telephone numbers of the subscriber's telephones until one is answered) or in parallel (ringing many telephones at the same time and delivering the call to the one that answers). These systems tie up network resources, especially when the subscriber has more than two telephones. Further, the calling party has to wait for the service to attempt all of the calls, which can cause the caller to give up, further wasting network resources. Therefore, there is a problem in the art that a subscriber with a wireless telephone and a wireline telephone cannot use one DN without manual action or tying up expensive network resources.